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Video: Homebuilt motorcycle with a supercharged, two-stroke, 10-cylinder radial engine

Jan 18, 2022

Every once in a while, a motorcycle build crosses my desk that demands an article. This is one of those motorcycles.

Marek Foltis, a self-described “mad engineer” in the Czech Republic, built a supercharged, two-stroke, 10-cylinder radial engine for a vintage-inspired build that displays rare bravery, not to mention an impossibly rare sound.

Bistella 500
Here's a view from the right side. Photo by Marek Foltis.

"At engineering school, the first thing they teach you is that everything is about efficiency,” he writes on his site, where you can read more about the build. “Meaning how much available potential is really used. And they train you to hunt down those losses. But over time I started to see some losses in people around me, and most importantly in myself. It really bugged me for a while. I just couldn't figure it out. Then I kinda connected the dots. People are frightened of trouble and failure which come up when you strive for something of value.”

Most motorcyclists would anticipate trouble and failure when attempting builds like his, I think. His senior project in high school was attaching a homebuilt jet engine to a moped, and the complexity seems to go up from there.

Bistella 500
Another view of the engine's design. Photo by Marek Foltis.

“The main goal [with the Bistella 500] was to create my own engine design, something that had never been used before in any vehicle,” he writes. The engine case, crankshaft, penta-supercharger assembly, and connecting rods were made on CNC mill. One carburetor feeds all 10 intakes. Amazingly, the cylinders, pistons, transmission case, and clutch are all Jawa parts. 

Bistella 500
A single carb feeds all 10 intakes through a nightmarish manifold. Photo by Marek Foltis.

Starting with a Jawa (appropriate for a Czech builder) as the base for the Bistella, Foltis stripped the bike down and began designing a twin-star radial that would a) actually work, b) fit within the stock frame, and c) be fully road-legal. Only a handful of motorcycles have ever been built with radial engines, let alone with a stacked 10-cylinder layout. The design also had to accommodate the five tiny Roots-style superchargers he wanted for boost and improved scavenging. The bike has a claimed weight of 341 pounds.

Foltis hopes his project inspires others to give their dreams a chance. “I never gave up,” he writes. “I worked on projects even when I didn't feel right. [For the] last few weeks, I literally hated to be in the workshop and push this project forward… The project is finished [and the] motorbike is running smoothly. I hope that my story will make some other guys' and gals' day better and entertain them for a few minutes by reading or watching videos about my adventure.

Bistella 500
Sure, the engine blew five times in development, but he reached his goal in the end. Photo by Marek Foltis.

“It would make all this work and suffering worthwhile if I could manage to inspire even one person to adopt responsibility for fulfilling one's dream and push against odds, never give up, don't change direction when things get tough.”